Looks like shareholders got left holding the bag on this one. How soon until the lawsuit comes for all those who have lost a fortune the last couple of days? Sadly the lawsuit if it comes will drive SIGA's stockprice even lower.
Plus the stock offering at just over $7 a share is in jeopardy. Unlikely that will happen now. My guess is it will have to be repriced at something less then $5 s share.
SIGA is in a death spiral for now. I recommend you wait to buy until it hits bottom. Wait for at least three days without a major lass to be more certain it has stop falling or risk losing a fortune. Be patient wait until it really its bottom before you buy and lose more money.
If you already hold shares pray for a bounce on Monday after the company hypes the shares and tries to pump up the price and again and sell if the stock can hold above $5 a share. If it drops below $5 a share on Monday again you might consider holding if you can stomach this risk. But, at anything above $5 a share just get out and count yourself lucky to at least get part of your investment back.